Transformer core winding apparatus



Sept. 3, 1963 M. c. UHRAIN TRANSFORMER CORE WINDING APPARATUS FiledApril 2, 1959 4 Sheets-Sheet 1 INVENTOR MICHAEL C. UHRAIN BY j @:.7?ATTOR EY iV- m TRANSFORMER CORE WINDING APPARATUS Filed April 2, 1959 4Sheets-Sheet 2 O I IO N IO MICHAEL c. UHRMN Sept. 3, 1963 M. c. UHRAIN3,102,697

TRANSFORMER CORE WINDING APPARATUS Filed April 2, 1959 4 Sheets-Sheet 3FIG. 5

FIG. 4

L NVE'NTU K MICHAEL c. UHRAIN Sept. 3, 1963 M. c. UHRAIN TRANSFORMERCORE WINDING APPARATUS 4 Sheets-Sheet 4 Filed April 2, 1959 INVENTORMICHAEL C. UHRAIN WI ATTORN Y United States Patent Ofi Eflhldh? FatentedSept. 3, 1953 ice Ohio

Filed Apr. 2, 1959, Ser- No. 303,753 2 Claims. (iCl. 242---9) Thisinvention relates to apparatus for winding electrical transformer cores,and more particularly to the winding of single-phase transformer coresof rectangular shape, and to three-phase transformer cores having a pairof adjacent rectangular components which are overwrapped to provide thethree legs of the core, each of uniform cross-section throughout anappreciable portion of its length to receive the primary and secondarywindings. While the electrical advantages of wound core transformershave been recognized for many years, the practical production of thecores for these transformers has heretofore been rather ditficulthecause no provision has heretofore been made to maintain constanttension in the silicon strip as the same is wound on to the rectangularcoil form with the resultant wobbling action of the coil being built upon the form. It is accordingly one of the objects of the presentinvention to provide an improved method and apparatus for continuouslyfeeding the silicon strip to a core winder embodying a rotatingrectangular form while simultaneously and continuously imparting therequired back tension in the strip, and also varying the rate of feed ofthe strip to compensate for variation in the radius of the coil beingwound as the coil form rotates.

A further object of the invention is the provision in apparatus of thekind mentioned above of means for accurately and continuously aligningthe side edges of the silicon strip being payed onto the coil beingwound with the plane of the end surface of the coil portion alreadycompleted so that in the finished product the side edges of eachconvolution of the coil are accurately aligned.

It has heretofore been proposed to construct the core for a three-phasewound-core transformer in the manner indicated in FIGURE 8 of theaccompanying drawing wherein a pair of separately Wound rectangular corecomponents A and B are brought into back-to back engaging contact and,while so related, areoverwrapped with silicon strip, as shown at C.There are thus provided in the finished core three legs D, E and F, forreceiving the pri mary and secondary coils of the transformer and itwill be understood that these legs will he of balanced crosssection ifthe number of turns in each of the components A, B and C are the same.

Another of the objects of the invention is the provision of an improvedmethod and appaartus for producing the assembly of FIGURE 8 in a rapid,economical manner. Thisis accomplished in my invention by winding thecomponents A and B in adjacent positions and in the same plane and,while these components are yet retained on the winding forms andspindles, they are brought forceably together in back-to-back relationafter which laoth are rotated about the common axis to apply theoverwrap component C.

A further object of the invention is the provision in core windingapparatus of improved means for controlling the speed of operation ofthe assembled apparatus, the tension in the silicon strip being wound,and providing for the stoppage of the winding operation while the stripsupply remains under tension. The latter feature permits the Wound coreor component to he securely bound before the strip supply is severed sothat'the finished product is compact and tightly wound as required.

The above and other objects and advantages of the invention will becomeapparent upon consideration of the following specification and theaccompanying drawings wherein there is disclosed certain preferredembodiments of the invention.

In the drawing:

FIGURES l and 2 are side elevation and plan views, respectively, of anassembled hack-tensioning payoff device and core winder constructed inaccordance with the principles of the invention;

FIGURE 3 is a horizontal sectional view of the geared drive utilized inthe core winder of FIGURES 1 and 2;

FIGURE 4 is a fragmentary vertical section view of the main shaft and aspindle support utilized in the core winder of FIGURES 1 and 2;

FIGURE 5 is the fragmentary vertical section view of a spindle supportand position adjusting means therefor utilized in the winder of FIGURES1 and 2;

FIGURES 6 and 7 are fragmentary vertical section and front elevationviews respectively, of a modified form of core winder constructed inaccordance with the principles of the present invention; and

FIGURE 8 is a side view of a completely wound core of a three-phasetransformer produced in accordance with the principles and by use of theapparatus of the present invention.

Referring now first to FIGURES 1 and 2 of the drawing, this embodimentof the core winder of the invention comprises asulb-base 10 on which isslidably mounted an integral base and gear case 11. As shown in FIGURE1, the base Ill is anti-cfrictionally mounted on the sub-base it? bymeans of the rollers 12 and guide rollers 13 whereby the base 11 withall the apparatus carried thereby may be moved outwardly and inwardly asviewed in FIGURE 1. To eifect such movement, and for a purpose to belater described, a double-acting fluid cylinder 14 is carried by thesub-base 10 and is interconnected with the base ll so that uponactuation of the cylinder the base may be moved inwardly or outwardly.

As shown more clearly in FIGURE 3, the base 11 journals a heavy hollowshaft 15 whose forwardly projecting end rigidly mounts a drum 16. in themanner more fully shown in FIGURES 4 and 5,. the drum 16 supports aspaced pair ofdiametrically extending screws 17 which are journaledadjacent their end portions in bearings 18 carried by a structuralmember 19 of the drum. Extending parallel with the screws 17 and formedas structural members of the drum 16 are ways 2! to slidably receive apair of blocks 2 lone on either side of the center of the drum. As shownin FIGURE 5, the blocks 21 are provided with locked threaded nuts '22 sothat upon rotation of the screws 17 the blocks 21 may be moved towardand away from the axis of rotation of the drum 16. Of course, theopposite end halves of the screws 17 are oppositely threaded so thatboth blocks 21 move inwardly or outwardly simultaneously and in equalincrements. Each of the blocks 21 journals: an outwardly extendingspindle 23, and the various parts are so assembled that the axes ofrotation of the spindles 23 are always equidistant from the axis ofrotation of the drum 16.

To rotate the screws 17 and thus to move the spindles 23 toward or awayfrom each other, as explained above, a worm gear 24- is keyed to each ofthe screws 17 and these gears are arranged to be driven by a worm 25which is in turn driven by an air motor 25. To supply air to the motor26, a double-passaged conduit 27 (FIG- URE 3) extends through the hollowmain shaft 15, and a rotary seal 28 of conventional, known design isattached to the rear end of conduit 27 to supply air pressure to eitherpassage, as is well known in the art. To the opposite, or drum end, ofthe conduit 27 there are attached conduits 29 which are located withinthe drum and lead to the air motors 26 (normally two such motors areused 3 one at each end of the screws 17). Thus by the use of suitableair supply and valving means, not shown, an operator may cause thespindles 28 to move inwardly or outwardly under remote control, asdesired. V

To the rear end of each spindle 23 there is rigidly secured a toothedclutch part 3d, and when the spindles 23 are moved to their outer-mostlimiting position the spindles and the clutch parts 30 are axiallyaligned with a pair of drive shafts '31 (see FIGURE 3) journaled in thebase 11. As shown, the shafts 31 extend forwardly of the base 11 and tothe outer free end of each is rigidly secured a complementary toothedclutch part 32. An internally-toothed sleeve 33 is longitudinallyslidable over each pair of clutch parts 30, 32, and when in bridgingrelation, as shown in FIGURE 3, these sleeves mechanically couple theparts 32 with the parts 3t? so that rotation of the shafts 31 drives thespindles 23. When the sleeves 33 are retracted to overlie only theclutch parts 32 the driving interconnections are broken and the drum andspindles are free to rotate with the main shaft 15. In actual practice atapered pin, not shown, slidably mounted in a block 34 (FIGURE 2) thatis rigidly carried on the base 11 is utilized to enter a taperedaperture, also not shown, in the back wall of the drum 16 to properlyindex the rotational position of the drum to obtain alignment of thespindles 23 with the drive shafts 31. To actuate this tapered pininwardly and outwardly under remote control I provide a double-actingfluid cylinder 35.

Referring now particularly to FIGURE 3, it will be observed that a gear36 is keyed to each of the shafts 31 andinterconnecting the gears 36 isa bull gear 37 which is jonrnaled on the main shaft 15. Driving one ofthe gears '36 is a pinion 38 which, through a gear reduction 39, isdriven by input shaft 40. Shaft 40, in turn, is power-driven through anelectromagnetic coupling 41 driven by an electric motor 42.. It will beunderstood by those familiar with the art that the coupling 41 may beremotely controlled by means, not shown, to predetermine the maximumtorque transmitted by shaft 40. In such systems when the torquerequirement of the load exceeds this predetermined setting, the shaft 40will merely stall while continuing to exert the preset torque eventhough the motor 42 continues to run at rated speed Interconnecting thebull gear 37 and the main driving shaft 15 is a mechanical toothedclutch 43, the movable part 44 of which is arranged to be actuated by arockshaft 45 which extends outside of the gear case and is normallyactuated by a double acting fluid cylinder, not

shown. Of course, when the machine is set up to drive the spindles 23through shafts 31 the clutch 43 is disengaged so that the bull gear 37freewheels on the shaft 15. When it is desired to rotate the drum 1-6the bridging clutch sleeves 33 associated with the spindles 23 areretracted, as explained above, along with the tapered indexing pinmounted in block 34. If the clutch 43 is engaged the drum 16 may now berotated under controlled power (torque) through a gear train consistingof input shaft 40, gear reduction 39', pinion 38, one of the gears 36,and bull gear 37.

Referring now to the silicon feeding and back-tensioning device usedwith the winding apparatus above described, and as shown in the leftportions of FIGURES 1 and 2, the same is mounted on an unitary base 50.To facilitate threading and observation I prefer to mount all the rollsand passes of this assembly in over-hung relation on the base t. First,I provide a deburring pass to roll down any sharp edges of the stripwhich may have been caused by prior slitting operations, for example,and this pass includes a hardened lower roll 51 which is mounted forrotation about a fixed axis extending outwardly from the base 50, asshown. A hardened upper roll 52 is journaled in a pair of spaced arms 53which in turn are welded onto a heavy cantilevered shaft 54 that extendsparallel with the axis of rotation of the roll 4 51. To provide a propercontrolled working pressure between rolls 51 and 52 a crank arm 55 isrigidly secured to the shaft 54 and is arranged tobe actuated by a fluidcylinder 56.

From the deburring pass 51, 5,2 the silicon stnip passes through a pairof adjustable Side guides 57 and thence over a back-tensioning roll 58carried by a cantilevered shaft 59. For a purpose to be later described,a holddown roll 60 is journaled in apair of spaced brackets 61 carriedby a cantilevered shaft 62. To apply proper pressure between rolls 58and 60 a crank arm 63 is rigidly secured to the shaft 62 for actuationby a fluid cylinder 64.

shaft 66. To effect maximum wrap of the strip on the roll 65 I providean idler roll 67 which, as shown in FIGURE 1, is positioned forwardly ofthe first ten sion roll 58. From the idler roll 67 the strip is wrappedaround a light-weight dancer roll 68 carried by the lower end of aflexing leaf spring 69 in such manner as to be normally positioned belowtheidler roll 67. Leaf spring 69 is in turn carried at its upper end ona cantilever shaft 70 which is controllably biased in a clockwisedirection as viewed in FIGURE '1 by a diaphragm-type of air motor 71acting through a crank arm 72 rigidly secured to shaft 70. The diaphragmmotor 7-1, which may be of the kind known commercially as aRotochamber," is frictionless in operation and if a suflicient volume ofair under pressure is connected thereto will provide the same resistanceto movement throughout its working range. Thus, during the winding ofrectangular coils, Where the larger winding radii are encountered at thecorners, the necessary momentary increase in the speed of the stripgoing into the winder is permitted by the movement of the dancer roll 68to the right as viewed in FIGURE 1 without any increase in theback-tension of the strip. This is due to the uniform clockwise biasapplied to the carrier for roll 68 by the diaphragm air motor 71. Abumperroll 73 limits the clockwise movement of the roll 68.

By relying primarily on the diaphragm air motor 71 to effect thecontrolled bias on roll 68 the spring 69 'may be made quite stifif toabsorb all the momentary shocks which may otherwise be transmitted tothe shaft 70. In a representative installation of the apparatus wherethe air motor'is so used spring 69 was replaced by a tubular arm whichappeared to provide sufficient shock absorbing capacity. It is alsowithin the purview of my invention to dispense with the air motor 71 andto rely entirely on the spring action of spring 69 to properly bias theroll 63, which arran-gementshould work satisfactorily if the momentarytake-ups in the strip are not severe.

As shown in FIGURE 1, the strip is fed onto the cores being wound overthe pair of idler rolls 74, 75 mounted on the winder housing 11 andpositioned so that the strip will at all times contact both :of theserolls and thus lie always in the same plane between these rolls. Mountedin this plane is an edge detector 76 which, as is well known to thoseskilled in the art, operates to produce an air or other signal when theedge of the strip deviates from a predetermined line of travel. Thisdetector is coupled through suitable relay valve means, not shown, tocontrol the actuation of the double-acting cylinder 14 so that the edgesof the convolutions being wound may be automatically and accuratelyaligned. if, for example, the edges cf the convolution being wound beginto drift outwardly from the predetermined desired spacing from the faceof drum 16, the error will be detected by the device 76 to move thewinder base 11 in a direction which is toward a viewer of FIGURE 1. havethe effect of gradually reestablishing the side edge alignment of theconvolutions being paid onto the coil. In normal operations thecorrection required is slight This will because the strip feeding andbackatension assembly inheren-tly tends to deliver strip along aconstant lateral path.

Back-.tensioning rolls 58 and 6 5 are, of course, keyed on the shafts 59and 66, respectively, and these shafts are interconnected by suitablegearing shown schematically at 77 while shaft 66 is coupled to theoutput shaft of a worm reducer 78. The worm shaft 79 of the reducer 78is double-ended, as shown, and is connected at one end with a smallmotor it operated through a variable magnetic coupling 81. To the otherend of shaft 79 is coupled a suitable speed control device 82 which, inactual practice, may take the form of a positive displacement hydraulicpump in the output conduit of which is located :a speed control valve,not shown. It will be understood that as this valve is progressivelytbrottled down the rolls '68 and 75 will turn at less and less speed-lowenergization and resultant slip in coupling 8 1 permitting thisand inthis manner the speed of strip payed off may be controlled. The drivemotor 80 is not only useful in overcoming running friction of the partsduring normal operation of the apparatus, but is also used forthreading. In the latter case it should be observed that upon retractingthe pressure rolls 52 and 60, the leading end of the coil of the stripstock may be inserted sideways or longitudinally into the apparatus withthe forward end projecting past roll 60. With the motor 8!) energizedand coupling 81 at full slip due to lockage at unit '32 and withcylinder 64 energized to bring roll 60 hard down on the strip, the stripmay be caused to move forwardly forthreading purposes simply bycontrollably opening the throttle valve for unit 82. In this mannerenough strip may be payed off to be attached to a form, not shown, onone of the spindles 23, and to be entrained over the various rolls asshown in FIGURE 1.

To operate the combined apparatus described above, the strip is threadedand attached to core form as explained immediately above. At this timethe pay-off stand is locked by closing the throttle valve for unit 82,for example, and the winder is also locked by ener-gization of amagnetic brake 83 which is on the drive shaft 49 of the winder. Withmotor 42 energized and brake 83 released, tension will be built up inthe strip at the point of winding to an amount determined by theintensity of excitation of the magnetic coupling 42, as will beunderstood, but the winding will not progress beyond this pick up pointbecause of lockage in unit 82. Sufficient air pressure is furnishedmotor 71 to retain the dancer roll 68 with the strip entrained thereoverin light pressure contact with the bumper roll 7.3. It now the throttlevalve for unit 82 is opened, winding of the coil will proceed at a rateof strip travel determined by the setting of the valve. As the windingproceeds, the outer convolution may be continuously ironed out by smallfollow-rolls 85 which are yieldingly urged toward the axis of rotationof the core being wound by an arm 86 actuated by a fluid cylinder 87.Also during the winding the edges of the core will be maintainedstraight by operation of the edge detector 76 acting through cylinder 14as described above. Inasmuch as the magnetic coupling 41 is a constanttorque device, the tension in the strip will remain substantiallyconstant regardless of the speed at which the core is wound. Of course,as the core builds up in diameter greater torque will be required tomaintain the same strip tension and, in actual practice, this isaccomplished by increasing the intensity of energization of the coupling41 by suitable and conventional control apparatus, not shown.

Upon the core being completed the device 82 is controlled to firstdecelerate the strip movement and to thereafter bring the rolls 58 and 65 to a halt. Since the torque transmitted by the coupling 41 is limited,the winding spindle and core formed thereon will slow up and come to ahalt during this interval while yet maintaining the same tension in thestrip. After the rotation of the core is stopped the outer convolutionof the core may be suitably bound to prevent unraveling after severanceof the strip. Prior to such severance the coupling 41 may be totallyde-energized to reduce the torque to zero and the brake 83 released toallow the tension in the strip to be relieved before the strip is cut.At this time the drum 16 may be indexed 180 to bring an empty core formadjacent the roll 65 for winding a second core in a manner repetitive ofthat outlined above. I When winding three-phase cores of the kindsuggested in FIGURE '8, the two core components (A and B) may be broughtforceably together by first retracting the clutch sleeves 33, aligningvertically the peripheral surfaces of the core components which are tobe engaged, and thereafter energizing the air motors .26 to rotatescrews 17 (FIGURE 5) to move the core components into pressureengagement with each other. Now the strip is secured to the compositeperiphery of the core components and the clutch 43 (FIGURE 3) isengaged, whereupon'the entire core assembly and drum is rotated to applythe outer wrapping C. Again, the torque is increased to effect propertension in the strip by controlling the coupling 41, and the windingoperation is started and stopped in the manner described above for asingle core.

In the modification of the invention illustrated in FIG- URES 6 and 7,the shaft 15a corresponds generally in structure and function with theshaft 15 in the first de scribed embodiment. Again, shaft 15a carries adrum 16a which corresonds generally in structure and function to thedrum 16. There is also provided a pair of blocks 21a which correspond infunction but not in structure with the blocks .21 of the first describedembodiment. These blocks 21a, instead of being mounted in ways andpropelled by screws, are slidably mounted on a pair of guide rods 90which are carried by and extend directly across the drum 16aequidistantly on opposite sides of the axis of rotation of the drum. Asin the case of the blocks 21, each of the blocks 21a rotatably supportsa core winding spindle 23.

Each of the blocks 21a has a rack gear portion 21b which faces inwardlytoward the axis of the drum 16a to engage a pinion gear 91 which isconcentrically disposed on said axis. Gear 91 is carried by a shaft 92journaled longitudinally in the main hollow shaft 15a and, as shown inFIGURE 6, a worm gear 93 is keyed to the outwardly extending rear endportion of shaft 92. Suitably secured to the rear end face of the shaft15a is a housing 94 which carries a worm 95 driven by a rotary air motor96. This motor also carried by housing 94, may be of a kind knowncommercially as a Gast motor. It is reversible-having a. pair of portseither of which may be selectively employed as an inlet port. Forsupplying air to these ports I provide a doublepassaged rotary seal 97which is connected to suitable conduit means 98.

When a single core is being wound on the embodiment of FIGURES 6 and 7,the drum 16a is, of course, held stationery, the clutch 43 isdisengaged, as explained above, and air is supplied to motor 96 in suchdirection as to hold blocks 211:1 outwardly in their proper positionsagainst stops 99 to locate the axes of spindles .23 on the axes of thedrive shafts 31 (FIGURE 3). When it is desired to bring the two Woundcore components together in making the threeaphase transformer, thedifixed outer housing of the rotary seal 97, which is connected to theconduit 98, remains stationery.

It should now be apparent that I have provided imclosed are equallyoperative for Winding either round,

rectangular, or other shaped cores or core components. The abovespecifically described embodiment of the invention should be consideredas illustrative only, as obviously many changes will be made thereinwithout departing from the spirit or scope of the invention. Forexample, in the matter of the edge control whereby the successiveconvolutions being built up on the core are kept aligned I may, insteadof moving the base 11 on the winder, mount the base 50 of theback-tensioning pay-off stand in a transversely movable manner forcontrol by device 76 to correct the side shifting of the strip as itenters'the core being wound. Reference therefore should be had to theappended claims in determining the mounted for rotation on said axis,each of said blocks having a rack portion meshing with said gear wherebyupon rotation of said gear with respect to said carrier said blocks willbe moved equally inwardly toward or outwardly away from each other, aspindle journaled in each said block for rotation about axes parallelwith the first mentioned axis, and means to alternately lock said piniongear with respect to said carrier and to rotate said pinion gear withrespect to said carrier;

2. Apparatus according to claim 1 further including a hollow shaftjournaled for rotation on said first mentioned axis for driving saidcarrier, and inner second shaft extending longitudinally in said hollowshaft and journ aled therein, said pinion gear being carried by anextending end of said second shaft, and means carried by the oppositeend of said hollow shaft to lock second shaft against rotation withrespect to said hollow shaft or alternately to rotate said second shaftrelative to said hollow shaft.

References Cited in the file of this patent UNITED STATES PATENTS2,006,628 Cline July 2, 1935 2,108,664 Franze Feb. 15, 1938 2,281,965Wylie May 5, 1942 2,295,327 Bendz Sept. 8, 1942 2,401,676 Weber June 4,1946 2,590,665 Williams Mar. 25, 1952 2,655,717 Dunn Oct. 20; 19532,660,380 Blackman et al Nov. 24, 1953 2,726,819 Zander et a1. Dec. 13,1955 2,735,630 Ziebolz Feb. 21, 1956 Hill May 12, 1959

1. APPARATUS FOR WINDING A CORE OF A THREE-PHASE TRANSFORMER COMPRISINGIN COMBINATION A POWER-DRIVEN ROTATABLE CARRIER, A PAIR OF BLOCKSMOUNTED ON SAID CARRIER ON OPPOSITE SIDES OF THE AXIS OF ROTATIONTHEREOF, GUIDE MEANS ON SAID CARRIER FOR GUIDING THE MOVEMENT OF SAIDBLOCKS TOWARD AND AWAY FROM SAID AXIS, A PINION GEAR MOUNTED FORROTATION ON SAID AXIS, EACH OF SAID BLOCKS HAVING A RACK PORTION MESHINGWITH SAID GEAR WHEREBY UPON ROTATION OF SAID GEAR WITH RESPECT TO SAIDCARRIER SAID BLOCKS WILL BE MOVED EQUALLY INWARDLY TOWARD OR OUTWARDLYAWAY FROM EACH OTHER, A SPINDLE JOURNALED IN EACH SAID BLOCK FORROTATION ABOUT AXES PARALLEL WITH THE FIRST MENTIONED AXIS, AND MEANS TOALTERNATELY LOCK SAID PINION GEAR WITH RESPECT TO SAID CARRIER AND TOROTATE SAID PINION GEAR WITH RESPECT TO SAID CARRIER.